body {
    /* background: #f2f2f2; */
    background: #282c34;
}

.frame {
    position: absolute;
    top: 50%;
    left: 50%;
    width: 400px;
    height: 400px;
    margin-top: -200px;
    margin-left: -200px;
    border-radius: 2px;
    box-shadow: 1px 2px 10px 0px rgba(0, 0, 0, 0.25);
    overflow: hidden;
    background: #9b59b6;
    color: #fff;
    font-family: 'Open Sans', Helvetica, sans-serif;
}

.ball {
    position: absolute;
    width: 50px;
    height: 50px;
    top: 175px;
    left: 175px;
    background: #fff;
    border-radius: 50%;
    animation: ball 2s ease-in-out infinite;

    .blur {
        position: absolute;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        background: rgba(255, 255, 255, 0.3);
        border-radius: 50%;

        --opacity: calc(1 - var(--i) / 10);
        --swing: calc(var(--i) * 7px);
        animation: blur 2s ease-in-out infinite;
    }
}

@keyframes ball {
    0%,
    100% {
        transform: translateX(-150px);
    }
    50% {
        transform: translateX(150px);
    }
}

@keyframes blur {
    0%,
    50%,
    100% {
        transform: translateX(0);
    }
    25% {
        transform: translateX(calc(var(--swing) * -1));
    }
    75% {
        transform: translateX(var(--swing));
    }
}
